A Boston Au Bon Pain sandwich shop is testing an iPad app for lunchtime sandwich ordering, according to this tweet and photo from Carl Howe of research firm Yankee Group.

We've never tried this, but as geeks, it seems pretty neat. (We could totally see some tacky high-end restaurant distributing iPads as menus in the next year or so.)

But as for the local sandwich shop, it seems like this could be a bit more trouble than it's worth.

Sure, it digitizes the process a bit -- Au Bon Pain has typically asked customers to customize their sandwich using a paper form and pencil -- but it adds a learning curve and a new point of failure, too.

On the other hand, it makes the menu infinite, allows for more and better promotions, and saves a bunch of trees.

We'd have to know more about the relative costs (how much does an Au Bon Pain location spend on order forms and pencils over the span of a year or two?) and benefits before we declare this a fad or "the future." We'd also have to see how easy-to-use and well-designed the app is versus the paper form.

Would customers be able to use their own iPhone or iPad app to order, too -- like Chipotle -- or just company-owned? (Au Bon Pain doesn't have an app in the App Store yet, as far as we can tell.)